1. Field of the Invention
The present invention relates to a semiconductor package and a semiconductor package mounting method. In particular, the invention relates to a semiconductor package for which it is easy to verify the orientation when mounting the semiconductor package onto a substrate and a semiconductor package mounting method.
2. Description of Related Art
Conventionally, mounting of semiconductor packages onto substrates has mainly been performed by the following two methods.
A first method involves image recognition of a lead location using a camera above the semiconductor package and verifying the orientation of the semiconductor package, after which the semiconductor package is mounted on the substrate and reflowed.
A second method involves image recognition of a lead position using a camera below the semiconductor package, after which the semiconductor package is mounted on the substrate and, after the orientation of the semiconductor package is verified by a camera above the mounted semiconductor package, it is reflowed.
In both cases, when verifying the orientation of the semiconductor package, it is determined whether the orientation is correct or not by image recognition of the shapes of chamfered corners of the semiconductor package. To be specific, as shown in FIG. 13, each of the corners of a semiconductor package 1 is chamfered, and the chamfer dimensions of one corner are made different from those of the other corners. It is determined whether the orientation of the semiconductor package is correct or not by image recognition of the location of the corner whose chamfer dimensions are different. When determining whether it is correct or not, a specified threshold value is set so as to determine whether there is a chamfer or not, and if it is determined that this threshold value is exceeded then the orientation is incorrect.
An example is proposed in Japanese Unexamined Patent Application, First Publication No. 2000-49446, wherein the direction of a semiconductor package is verified and then the semiconductor package is mounted on a substrate, so that the mounting location accuracy is improved.
However, since corner chamfer shapes of semiconductor packages differ depending on the semiconductor package assembler, in a case of mounting semiconductor packages manufactured by a plurality of assemblers, there is an inconvenience in that the image processing threshold value for image processing must be set for each assembler corresponding to the difference and dispersion of the chamfer dimension settings.
Furthermore, since the invention proposed in Japanese Unexamined Patent Application, First Publication No. 2000-49446 involves marking the substrate mounting side, and the location of a semiconductor package is determined by this marking, the direction of the semiconductor package can only be verified after mounting. Therefore, it is not possible to determine whether the direction of the package is correct or not by verifying the direction of the semiconductor package before mounting.
Furthermore, the prior art does not have a mechanism for recognizing the direction of a semiconductor package and rotating it to the correct direction. Therefore, there is a problem in that a semiconductor package placed in a tray or the like in an incorrect direction remains in the incorrect direction when mounting.